Full-color LED-based lighting device

Abstract

A LED full-color lighting device contains a control unit, a light source unit, and a light display unit. The control unit relies on at least a potentiometer to apply various voltages to constant current sources, which in turn individually vary the current conducting through the red, green and blue LEDs of the light source unit, so as to deliver light of various colors. The colored light emitted from the light source unit can be easily and conveniently adjusted to fit a user's specific preference and mood. Colored patterns or textures can be formed on the light display unit so that the color of the light of the light source unit would mix with the colors of the patterns or textures to produce a visual effect as if some of the patterns or textures are changed.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention generally relates to lighting devices, and more particularly to a lighting device providing individual adjustment of the brightness of red, green, and blue light emitting diodes (LEDs) for full-color illuminating and presentation effects on the lamp shade or screen by controlling the amount of current flowing through the LEDs.[0003]2. The Prior Arts[0004]Currently, most of the LED-based color lamps available in the market provide various colored light by individually turning on and off the red, green, and blue LEDs of the lamp. For example, a control circuit of the lamp provides a 3-bit digital signal with each bit controlling whether to turn on (1) or off (0) the red, green, and blue LEDs, respectively. The lamp is therefore able to generate light of seven different colors, including red (001), green (010), blue (100), red plus green (011), green plus blue (110), blue plus red (101), and red plus ...

AI Technical Summary

Benefits of technology

[0007]Accordingly, a major objective of the present invention is to provide a LED-based lighting device in which the brightness of the LEDs can be varied continuously from complete darkness to full illumination so as to deliver light of theoretically unlimited number of colors (i.e., full-color).

[0008]Another objective of the present invention is that, in addition to the large number of possible colors, the lighting device does not rely on human visual persistence to compensate the flashes of LEDs, and therefore is able to deliver highly stable, flicker-free, and comfortable lighting no matter what the color and brightness are.

[0009]Still another objective of the present invention is to provide a low-cost, easy-to-operate, and multi-function lighting device that not only can function as an ordinary illumination device such as a desk lamp, a floor lamp, a wall lamp, etc., but, with its various colored light, also can be used to adjust a room's lighting condition so as to provide a soothing, relaxing, romantic, or even exotic atmosphere, to fit precisely the user's preference and mood.

[0010]To achieve the foregoing objectives, the lighting device of the present invention mainly contains a light source unit, a control unit, and a light display unit. The light source unit contains a number of red, green, and blue LEDs. The control unit relies on potentiometers to apply voltages of appropriate levels based on user adjustment to a number of corresponding constant current sources, respectively. The constant current sources thereby provide various amount of constant current through the red, green, and blue LEDs of the light source unit respectively. In other words, instead of using voltage or voltage pulses to control or drive the LEDs, the present invention controls the current flowing through the LEDs so as to adjust the brightness of the LEDs and thereby produces various color combinations. The stable provision of current of the constant current sources is the major factor contributing to the flicker-free and comfortable lighting of the LEDs.

[0011]Due to its capability in producing theoretically unlimited number of color combinations, the present invention can be applied for various purposes, with the light display unit playing an important role. The light display unit basically is a lamp shade or lamp screen, but it can be more versatile than that. The light display unit can be made of materials of appropriate transparency. Additionally, colored patterns or textures of appropriate transparency can be formed on the outer surface of the light display unit so that, as the color of light from the light source unit is varied, the colors of the patterns or textures would be varied as well, delivering different visual effect.

Problems solved by technology

However, adjusting the brightness of LEDs by voltage is difficult due to the specific semiconductor characteristics of LEDs.

A lamp based on the PWM-based approach therefore can only provide stable lighting in the medium-to-high brightness range and delivers only a small number of color combinations.

This technique would suffer the same drawbacks of the previous one.

Therefore, when a large number of LEDs are used, complicated heat dissipation mechanism has to be designed and employed, causing significant cost increase and reducing the applicability of the LED-based lamps.

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